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Submillimeter functional localization in human striate cortex using BOLD contrast at 4 Tesla: Implications for the vascular point‐spread function
Author(s) -
Me Ravi S.,
Goodyear Bradley G.
Publication year - 1999
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/(sici)1522-2594(199902)41:2<230::aid-mrm3>3.0.co;2-o
Subject(s) - striate cortex , contrast (vision) , function (biology) , vascular network , point (geometry) , nuclear magnetic resonance , cortex (anatomy) , visual cortex , neuroscience , anatomy , physics , biology , optics , mathematics , geometry , evolutionary biology
Using multislice segmented echoplanar imaging at 4 T, we have measured an upper bound to the cortical vasculature point‐spread function (PSF) using functional magnetic resonance imaging (fMRI) in humans. Our experiments demonstrate that cortical subunits that are approximately 700 μm apart can be resolved using the early part of the hyperoxygenation phase of the blood oxygenation level‐dependent (BOLD) effect. This was accomplished using brief (4 sec) single trials of monocular and binocular stimulation of ocular dominance columns in human primary visual cortex. The data suggest that at even higher magnetic fields, the cortical vasculature PSF may be limited by the extent and nature of horizontal connections and not signal‐to‐noise ratio. Magn Reson Med 41:230–235, 1999. © 1999 Wiley‐Liss, Inc.